1. Field of the Invention
The present invention is in the technical field of light sources, and more particularly, light sources useful in applications that requires high luminance, such as projection displays and stage lighting.
2. Description of the Related Art
Many applications need colored light, such as stage lighting, projection display, RGB backlighting etc. Conventional high luminance light sources used in special lighting and displays are gas discharge lamps. An environmental-friendly technology is described in U.S. Pat. No. 7,547,114. In this light source structure, shown in FIG. 1, a solid-state light source 100 is used to emit an excitation light through a focusing system 102, and a rotation phosphor wheel 104, in which several color phosphors are coated in different segments, is excited by the excitation light source to generate a light with a colored light sequence. A is the rotation axis of the color wheel. Phosphor materials are wavelength down conversion materials, which means that they can absorb shorter wavelength photons and emit longer wavelength photons. Other wavelength down conversion materials useful in the above device include quantum dots, etc.
In the prior art described by U.S. Pat. No. 7,547,114, the multiple colors are generated sequentially. When the phosphor wheel's red phosphor segment is moved to the excitation position, red phosphor will be excited and red color light will be generated. The same thing happens for a green phosphor segment or a yellow phosphor segment.